The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a fracturing/gravel packing tool system with dual flow capabilities.
In conventional fracturing and gravel packing operations, a slurry is typically mixed to a desired density at the surface and then pumped into a well via a work string. Several factors limit the rate at which the slurry can be pumped through the work string. Among these factors are resistance to flow through the work string and erosion of the work string and other equipment.
In the past, such limitations have been dealt with by increasing the size of the work string to reduce flow resistance, and increasing the erosion resistance of the equipment. However, these solutions have been only partially successful. For example, in smaller casing sizes it may not be possible to substantially increase the size of the work string.
Furthermore, where the work string is thousands of feet long, changes in the slurry density cannot be quickly made to cope with unexpected circumstances, uncertainty in reservoir characteristics, or to enable selective fracturing of layers. Instead, changes in slurry density are made at the surface and the existing slurry already in the work string must be displaced before the changed density slurry reaches the formation.
Therefore, it may be seen that improvements are needed in well treatment systems and methods. It is among the objects of the present invention to provide such improvements.